Wireless Charging Sonic Electric Toothbrushes
WAS-1972EN V1.00
5 / 17
December 27, 2021
In terms of wireless charging transmission and data reception, the charging base uses a BP45F0044
integrated high voltage NMOS and a programmable PWM circuit to control the LC resonance
circuit to transmit wireless charging power. An integrated demodulation circuit is used to receive
wireless charging data. For the sonic motor and lithium battery charging control, the toothbrush
body uses a BP45F1330 integrated H-bridge drive circuit to control the sonic motor and uses an
integrated linear charging circuit for lithium battery charging management. The charging base and
toothbrush body hardware will be introduced below.
Hardware Description
Charging Base Hardware Block Diagram
Figure 3. BP45F0044 Charging Base Hardware Block Diagram
USB input
The charging base is a 5V voltage system, which uses a high voltage NMOS transistor to control
the LC resonance.
Integrated demodulation circuit
The current is converted to a voltage signal using an OCPI input pin and is amplified by an
internal programmable operational amplifier PGA and is demodulated using the appropriate
CMP settings and then finally used for communication.
Toothbrush Body Hardware Block Diagram
Figure 4. BP45F1330
Toothbrush Body Hardware Block Diagram
